Stock 5.0 have 180-190HP at the wheels and you will NEVER have 325HP at the Wheel with Out heads Never well Maybe with Noss. 225 is at the Fly wheel
75MM is WAY to Big you are loseing Power with that On the stock heads.
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14.62@96.9 Engine: Steal Mounts, Under drive pulleys, K&N, Home ported Lower Intake, No power steering, No A/C
Drive Train: 3.55, World Class T-5, Lakewood Bell housing, Adjustable Clutch Cable, AL Driveshaft
Suspension: MAC Control Arms, Maximum Motorsports Front Grip Package, H&R Sport Springs, Bilstein Shocks
Exhaust: 1 5/8 UN-Equal Length Mac Headers, X-pipe W\cats, Edelbrock cat\back
Cooling: 3 Core Radiator